* {
    margin: 0;
    padding: 0;
}

li {
    list-style: none;
}

a {
    text-decoration: none;
}

body {
    background-color: #f5f3f7;
}

.w {
    width: 1200px;
    margin: 0 auto;
}

.clearfix:before, .clearfix:after {
    content: "";
    display: table;
}

.clearfix:after {
    clear: both;
}

.clearfix {
    *zoom: 1;
}

.header {
    margin: 30px auto;
    height: 42px;
}

.logo {
    float: left;
    width: 198px;
    height: 42px;
}

.nav {
    float: left;
    margin-left: 60px;
}

.nav ul li {
    float: left;
    margin: 0px 15px;
}

.nav ul li a {
    display: inline-block;
    padding: 0 10px;
    height: 42px;
    line-height: 42px;
    color: #050505;
}

.nav ul li a:hover {
    color: skyblue;
    border-bottom: 2px solid skyblue;
}

.search {
    float: left;
    width: 412px;
    height: 42px;
    background-color: skyblue;
    margin-left: 70px;
}

.search-input {
    float: left;
    width: 340px;
    height: 40px;
    border: 1px solid #00a4ff;
    border-right: none;
    padding: 0px 10px;
}

.search-button {
    float: left;
    width: 50px;
    height: 42px;
    background-image: url(../images/btn.png);
    border: none;
}

.user {
    float: right;
    height: 42px;
    margin-right: 30px;
    font-size: 14px;
    color: #666666;
    line-height: 42px;
}

.banner-bg {
    height: 421px;
    background-color: #1c036c;
}

.banner-container {
    height: 421px;
    background: url(../images/banner2_20190819_210028.png) no-repeat top left;
}

.leftnav {
    float: left;
    width: 190px;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.3);
}

.leftnav ul li {
    height: 45px;
    line-height: 45px;
    padding: 0 20px;
}

.leftnav ul li a {
    font-size: 14px;
    color: white;
}

.leftnav ul li a:hover {
    color: #00a4ff;
}

.leftnav ul li a span {
    float: right;
}

.course {
    float: right;
    width: 230px;
    height: 300px;
    margin-top: 50px;
    background-color: white;
}

.course h3 {
    height: 48px;
    line-height: 48px;
    font-size: 18px;
    text-align: center;
    color: white;
    background-color: #9bceea;
}

.course ul li h4 {
    display: inline-block;
    font-size: 14px;
    color: #4e4e4e;
    margin-left: 8px;
}

.course ul li {
    padding: 10px 20px;
    border-bottom: 1px solid #ccc;
}

.course-hint {
    font-size: 16px;
    color: #4e4e4e;
}

.course-progress {
    font-size: 12px;
    color: #a5a5a5;
}

.course-all {
    display: block;
    height: 38px;
    border: 1px solid #00a4ff;
    text-align: center;
    line-height: 38px;
    color: #00a4ff;
    font-size: 16px;
    font-weight: 700;
    margin: 8px 20px 0px;
}

.categories {
    /* 高度、行高会继承 */
    height: 60px;
    line-height: 60px;
    text-align: center;
    background-color: #ffffff;
    box-shadow: 0px 2px 3px 3px rgba(0, 0, 0, 0.1);
    margin-top: 10px;
}

.categories h3 {
    float: left;
    margin-left: 30px;
    font-size: 16px;
    color: #00a4ff;
}

.categories ul {
    float: left;
    margin-left: 30px;
}

.categories ul li {
    float: left;
}

.categories ul li a {
    padding: 0 30px;
    font-size: 16px;
    color: #050505;
    border-left: 1px solid #ccc;
}

.changeInt {
    float: right;
    margin-right: 30px;
    font-size: 14px;
    color: #00a4ff;
}

.recommends {
    margin-top: 30px;
}

.rcmd-header {
    height: 43px;
    line-height: 43px;
}

.rcmd-header h3 {
    float: left;
    font-size: 20px;
    color: #494949;
}

.rcmd-header a {
    float: right;
    font-size: 12px;
    color: #a5a5a5;
}

.rcmd-content ul {
    width: 1225px;
}

.rcmd-content ul li {
    float: left;
    width: 228px;
    height: 270px;
    background-color: white;
    margin-right: 15px;
    margin-bottom: 15px;
    position: relative;
}

.course-item img {
    width: 100%;
}

.course-item em img {
    width: 40px;
    position: absolute;
    top: 3px;
    right: -3px;
}

.course-item h4 {
    margin: 20px 20px 20px 25px;
    font-size: 14px;
    color: #050505;
    font-weight: normal;
}

.course-info {
    margin: 0 20px 0 25px;
    font-size: 12px;
    color: #999999;
}

.course-info span {
    color: #ff72cd;
}

.footer {
    height: 380px;
    background-color: white;
}

.footer-content {
    padding-top: 35px;
}

.copyright {
    float: left;
}

.frentlinks {
    float: right;
}

.copyright p {
    font-size: 12px;
    color: #666666;
    margin: 20px 0 15px 0;
}

.copyright a {
    display: block;
    width: 118px;
    height: 33px;
    line-height: 33px;
    text-align: center;
    font-size: 16px;
    color: #00a4ff;
    border: 1px solid #00a4ff;
}

.frentlinks dl {
    float: right;
    margin-left: 100px;
}

.frentlinks dl dt {
    font-size: 16px;
    color: #333333;
    margin-bottom: 5px;
}

.frentlinks dl dd a {
    font-size: 12px;
    color: #333333;
}
